A key U.S. senator said on Wednesday he was "somewhat appalled" by Aung San Suu Kyi's reaction to her country's record on human trafficking, underscoring concerns about human rights that are shadowing the Myanmar leader's visit to Washington.

"While we certainly appreciate the work Aung San Suu Kyi has done to ensure a democratic transition in Burma, I am somewhat appalled by her dismissive reaction to concerns I raised this morning about the problem of human trafficking in her country," Senator Bob Corker said in a statement released to Reuters after a breakfast meeting with Suu Kyi and Vice President Joe Biden.

"After witnessing her lack of regard for Burma's dismal track record on this issue, I plan to pay very close attention to her government's efforts to prevent innocent human beings from being trafficked and sold into forced labor and sex slavery," said Corker, the chairman of the influential Senate Foreign Relations Committee.